The present invention relates generally to gas turbine exhaust diffusers. More specifically, the invention relates to systems and methods for integrating heat exchanger elements, normally present in heat recovery steam generation (HRSG) systems, with components of gas turbine exhaust diffusers.
In combined cycle power generation systems, heated exhaust gas discharged from gas turbines may be used by HRSG systems as a source of heat, which may be transferred to a water source to generate superheated steam. In turn, the superheated steam may be used within steam turbines as a source of power. The heated exhaust gas may be delivered to the HRSG system through, among other things, an exhaust diffuser, which may help convert the kinetic energy of the heated exhaust gas exiting the gas turbine into potential energy in the form of increased static pressure. Once delivered to the HRSG system, the heated exhaust gas may traverse a series of heat exchanger elements, such as superheaters, re-heaters, evaporators, economizers, and so forth. The heat exchanger elements may be used to transfer heat from the heated exhaust gas to the water source to generate superheated steam. Both the exhaust diffuser and the HRSG may occupy a great deal of space within the combined cycle power generation plant. For instance, the exhaust diffuser, in many instances, may be as long as the gas turbine itself. In addition, the length of the HRSG may also be on the same order of magnitude. Therefore, it may prove beneficial to implement design strategies for reducing the overall footprint used by these two major components of the combined cycle power generation plant.